Is 1-10' A Common Twist in 6mm BR?

[jimfinn]

I recently bought a used barrel chambered in 6MM BR. Initially I thought it had a fast,1-7.5') twist. But after getting the rifle put together I took it for a test drive using 105 Hornady A-Max bullets. The velocities looked reasonable,2700'/sec out of a 31' barrel) and consistent. But bullets were key-holing and were scattered on the target.
So I figured I'd test my assumption on the twist of this barrel. Using the cleaning rod with tight nylon brush, a ruler and masking tape to mark the cleaning rod shaft, I consistently got a 1-10',or darn close given my measuring technique) twist. This would explain the results on paper.
I am new to this 6MM BR game and would like to know if a 1-10' twist is common in a long range,31' long 1.2' diameter, mounted with a block) barrel? According to Berger's website I should be keeping my bullets wieghts at or below 90 with this twist.
Thanks for taking the time to read a newbie's question.
Jim

 

[MT300RUM]

How many yards were you testing it at? i shoot 105's out of a
1-9 twist, with great results out to 735yds haven't tested past that, but i would sure think if you were under 400 yds you should be fine, in my little brain i would think the only need for the faster twist would be to stablize the heavier bullets down range, but at the shorter distances i wouldn't think it would make that big of a differance, i'm sure i'm gonna find out as soon as a couple of the guru's read this..

 

[skeetlee]

A ten twist is pretty standard for 6mm chamberings. The ten twist is an excellent choice, but not for the 105gr bullets. I would also agree with bergers web site. stick with 90gr or less. The 90gr berger bullet is a heck of a bullet and you will be surprised of the accuracy of this bullet out to 500 yards and maybe even more. If you really want to shoot the long heavies sell the 10 twist and go with an 8. Hope this helps a bit

 

[jimfinn]

Thanks for the feed-back.
I was only shooting at 100 yards today. I have to travel a fair distance to shoot over 300 yards.
I am not stuck on shooting the long heavy bullets, I was under the mistaken assumption that the twist on this barrel was fast just for shooting the heavy and long for caliber bullets.
I'll be heading back to the range next week and will go armed with a selection of lighter bullets.
Thanks for the tip on the 90 gr Bergers. I have about 30 that came with the barrel, along with some 80's and 88's. I got some 105 Bergers but from the sounds of it I'll see if I can find someone who can make better use of those ones.
Take care
Jim

 

[tiny68]

I have a 1:10 6BR. It will stabilize the Berger 95 VLDs. I don't thing all 1:10s will. Walt Berger told me it was hit and miss with each barrel. However, the 95 BIBs shoot great in the 1:10. Contact Randy Robinett and get a sample box and them they. You will get more. Luck, tiny

 

[12man]

Had great results with a 1-10 twist Lilja, 95 BIBs shoot awesome, and haven't really done much load testing. Loaded using data off this site and shooting great for no real experimenting. Also shoots the 65 Vmax 68 Berger 75 Vmax & 80 gr Bergers really good. Would like to try the 8o gr Fowlers

 

[MarkS]

Jim,

You will see more 14 tw & 8tw than 10tw. My 10tw is throated too long for the 95 Berger's, but is a great bullet, if it will stablize them. Mine likes 95 Bib's 90 & 88 gr Bergers for long range, 68 & 80gr Berger's for shorter ranges.

Mark Schronce

 

[jimfinn]

Thanks Mark,
Now I just need to order/find a selection of bullets to try. Locally in Alaska there isn't much in the way of target bullets in stock besides some Hornaday and Sierra's. I did pick up a box of 85 gr HPBT Sierras to try. Plus the other Bergers I mentioned that I have above. Work is pretty nuts right now, so I will not be able to get out for any long relaoding at the range sessions for a couple of weeks.
I'll at least try some of the lighter bullets this Sunday and make sure that key-hole problem is not happening with them too.
Jim

 

[tiny68]

Thanks Mark,
Now I just need to order/find a selection of bullets to try.

Jim,

This guys sells sample bullets from Sierra, Hornady, Nosler, and Berger. You can get just a few to try them out. Might save you buying a full box.

Luck, tiny

Sample Bullets

 

[jimfinn]

Well lighter bullets did the trick.
I have been too busy with work, etc. to spend real quality time at the range. But I did manage to get out last Sunday. I loaded some of the Seirra 85's seated to the lands with incremental charges of Varget, BL-C,2, and VihatVuori 540. They all shot well and without any further load tweaking shooting sub 0.5' groups is easy. I did Manage one three-shot group just over 0.1',all shot at 100 yards). Velocities ran up near 3000'/sec for the highest loads with no overt pressure signs.
This is my first time with this cartridge and I think this is going to be fun, heck it is already.
My next plan is to take some 80. 88, and even some 95 Bergers with preped cases to the range so I can tweak loads and seating depths right at the bench. If the weather holds, that is where I'll be this weekend!
Thanks for all the good advice and input.
Jim